The present invention relates to a motor vehicle theft-deterrent steering lock.
The invention relates more specifically to a motor vehicle theft-deterrent steering lock of the type comprising a casing in which a lock is mounted to rotate between an angular position of rest in which a compliant key can be introduced, from the rear forward, or withdrawn, axially, and at least one angular position of use in which the key cannot be extracted from the lock, the lock comprising a rotary deployment member forming a cam which is capable of collaborating with a control member borne by a lock bolt to control the movements of the latter which is mounted so that it can slide in the casing, in an axial direction, between a forward theft-deterrent position toward which it is elastically urged and in which it projects axially forward through an opening in the casing to prevent the rotation of a member of the steering column when the lock is in the position of rest, with the key extracted, and a rear position in which it is retracted into the casing.
Numerous designs of theft deterrents such as this are known and are usually employed to prevent the theft of vehicles, particularly the theft of private automobiles.
Numerous improvements have been made to theft deterrents of this type, particularly as regards the lock, so as to improve the ability of the theft deterrent to withstand the various methods of attack devised by vehicle thieves.
It has, however, been found that there is still a possible form of break-in during which the thief tries to actually act on the lock bolt itself to drive this into the casing of the theft deterrent and release the steering column.
French patent application FR-A-2.788.477 of Jan. 15, 1999 already proposes a new design of a theft-deterrent steering lock of the kind mentioned previously which remedies this drawback by preventing any possibility of driving the lock bolt into the casing when the theft-deterrent device is in a position of rest, that is to say in a position in which it immobilizes the steering column in terms of rotation.
To this end, that document proposes a motor vehicle theft-deterrent steering lock of the type comprising a casing in which a lock is mounted to rotate between an angular position of rest in which a compliant key can be introduced, from the rear forward, or withdrawn, axially, and at least one angular position of use in which the key cannot be extracted from the lock, the lock comprising a rotary deployment member forming a cam which is capable of collaborating with a control member in the form of a control finger borne by a lock bolt to control the movements of the latter which is mounted so that it can slide in the casing, in an axial direction, between a forward theft-deterrent position toward which it is elastically urged and in which it projects axially forward through an opening in the casing to prevent the rotation of a member of the steering column when the lock is in the position of rest, with the key extracted, and a rear position in which it is retracted into the casing, and of the type in which:
the lock bolt carries a retractable immobilizing finger which projects radially toward the axis to be housed in an immobilizing housing formed in a lateral face facing it belonging to the deployment member, of axial orientation, when the lock bolt is in the forward theft-deterrent position, to prevent or limit any movement of the lock bolt toward its retracted rear position; PA1 the immobilizing finger automatically moves out of the way as the lock is turned from its position of rest toward its position of use; PA1 and the lock bolt is held axially in the retracted rear position, in the presence of a key, by a lock bolt retaining member which is mounted so that it can move between a retracted position, when the key is absent, and a retaining position when there is a key present. PA1 the rear axial end of the immobilizing member is mounted to pivot with respect to the lock bolt and the immobilizing finger is formed at the front axial end of the immobilizing member; PA1 the return spring is an axially acting spring which is inserted between the casing and the immobilizing member; PA1 the return spring is a compression spring which is inserted between the casing and a rear bearing face of the body of the immobilizing member, and the axial line of action of the spring is located radially on the outside with respect to the transverse axis of articulation of the immobilizing member; PA1 the immobilizing member is linked in axial translation with the lock bolt whose movement-control member it forms; PA1 the immobilizing member is made as a single piece with the lock bolt; PA1 the immobilizing member is formed at the front free end of an elastic beam made as a single piece with the lock bolt and the rear end of which constitutes a hinge articulating the pivoting immobilizing member about its transverse axis; PA1 the return spring for the immobilizing member acts as a lock bolt spring to constantly axially urge the latter toward its theft-deterrent position; PA1 the part of the lock bolt which carries the immobilizing member is delimited radially toward the inside by an axial face in which there are formed means for the pivoting guidance of complementary means of articulation carried by the body of the immobilizing member; PA1 the lock bolt comprises a rear part which is housed inside the casing and the front end of which carries the immobilizing member.
In that document, the immobilizing finger is mounted to slide radially in the lock bolt against the action of a return spring which constantly urges it radially inward toward the immobilizing housing, and the immobilizing finger also acts as a control finger.
This design is satisfactory from the functional point of view but presents certain drawbacks which the present invention intends to overcome.
In particular, the design of the control and immobilizing finger, in which the movements thereof are guided so that it slides radially in a cylindrical sleeve, with an axial compression spring which constantly urges it, presents risks of jamming, particularly since transverse loadings are applied at the unsupported functional free end of the immobilizing finger.
Furthermore, this design requires a special-purpose return spring for returning the immobilizing finger and another spring for constantly elastically urging the lock bolt toward its theft deterrent position. Aside from the high number of components which this design demands, these components are also complex and expensive to assemble and it is difficult to attach the hollow cylindrical body to the sheet metal puller.
Finally, the body of the finger in the form of a sleeve which acts as a finger for controlling the movements of the lock bolt acts on the latter indirectly via a "top of the spline" spring, which also constantly applies loading to an unsupported part of the cylindrical finger body whose guidance in the axial aperture formed in the lock bolt is, moreover, difficult to control.
In order to remedy these drawbacks, the invention proposes a theft deterrent of the aforementioned type, wherein the immobilizing finger belongs to an immobilizing member carried by the lock bolt with respect to which it is mounted to pivot, around a transverse axis perpendicular to the axial direction of the sliding of the lock bolt, against the action of a return spring which constantly urges it angularly in the direction corresponding to the housing of the immobilizing finger in the immobilizing housing.
According to other features of the invention:
Other features and advantages of the invention will become apparent from reading the detailed description which will follow, for an understanding of which reference will be made to the appended drawings, in which: